Finding the Fourth Proportional to 131.16, 196.08 and 90.42

Step by Step Solution

1. Step 1: Write the proportion equation
   131.16 : 196.08 = 90.42 : x
2. Step 2: Convert to fraction form
   131.16/196.08 = 90.42/x
3. Step 3: Cross multiply
   131.16x = 196.08 × 90.42
4. Step 4: Simplify right side
   131.16x = 17,729.55
5. Step 5: Solve for x
   x = 17,729.55/131.16
6. Step 6: Final answer
   x = 135.18